From 492628ba784b21c46cf4c15740dc4d031d1d1412 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Thu, 27 Aug 2020 17:02:19 +0100
Subject: [PATCH 1/2] Use sparsity in B for Triangular * B and Triangular \ B

---
 src/mul.jl        |  1 +
 src/triangular.jl | 14 ++++++++------
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/mul.jl b/src/mul.jl
index deaaec3..999dcff 100644
--- a/src/mul.jl
+++ b/src/mul.jl
@@ -252,3 +252,4 @@ dot(a, b) = materialize(Dot(a, b))
 # We go to generic fallback as layout-arrays are structured
 dot(x, A, y) = dot(x, mul(A, y))
 LinearAlgebra.dot(x::AbstractVector, A::LayoutMatrix, y::AbstractVector) = dot(x, A, y)
+LinearAlgebra.dot(x::AbstractVector, A::Symmetric{<:Real,<:LayoutMatrix}, y::AbstractVector) = dot(x, A, y)
diff --git a/src/triangular.jl b/src/triangular.jl
index 7228da1..f101be5 100644
--- a/src/triangular.jl
+++ b/src/triangular.jl
@@ -29,10 +29,11 @@ function materialize!(M::Lmul{<:TriangularLayout{'U','N'}})
         throw(DimensionMismatch("right hand side B needs first dimension of size $(size(A,1)), has size $m"))
     end
     Adata = triangulardata(A)
-    for j = 1:n
-        for i = 1:m
+    for j = rowsupport(B)
+        cs = colsupport(B,j)
+        for i = cs
             Bij = Adata[i,i]*B[i,j]
-            for k = (i + 1:m) ∩ rowsupport(Adata,i)
+            for k = (i + 1:m) ∩ cs ∩ rowsupport(Adata,i)
                 Bij += Adata[i,k]*B[k,j]
             end
             B[i,j] = Bij
@@ -48,10 +49,11 @@ function materialize!(M::Lmul{<:TriangularLayout{'U','U'}})
         throw(DimensionMismatch("right hand side B needs first dimension of size $(size(A,1)), has size $m"))
     end
     Adata = triangulardata(A)
-    for j = 1:n
-        for i = 1:m
+    for j = rowsupport(B)
+        cs = colsupport(B,j)
+        for i = cs
             Bij = B[i,j]
-            for k = (i + 1:m) ∩ rowsupport(Adata,i)
+            for k = (i + 1:m) ∩ cs ∩ rowsupport(Adata,i)
                 Bij += Adata[i,k]*B[k,j]
             end
             B[i,j] = Bij

From 7fc4bf13c8b49bca98fcac2970e6c0d446e16f05 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Fri, 28 Aug 2020 14:19:52 +0100
Subject: [PATCH 2/2] Update Project.toml

---
 Project.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 06b8da2..6dd6f31 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 authors = ["Sheehan Olver <solver@mac.com>"]
-version = "0.4.4"
+version = "0.4.5"
 
 [deps]
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"